1. Field of the Invention
The present invention relates to a multilayer aluminum alloy plain bearing having superior compatibility and superior fatigue resistance which is to be used in high-power engines for automobile and general industrial machinery.
2. Description of the Related Art
As conventional well-known aluminum-based alloy bearing, Japanese Patent Examined Publication No. 62-14024 discloses a one in which a bearing alloy has an Al-Sn alloy layer and a back metal both bonded to each other through an intermediate bonding layer of Al or Al alloy which is low in hardness so as to form a bearing through machining, and Japanese Patent Unexamined Publication No. 3-168411 discloses another one in which a hard Al bearing alloy and a back metal are bonded to each other through a well-balanced reinforcing intermediate layer.
The former of these conventional bearings is excellent in compatibility and non-seizability which are important characteristics for the plain bearing. However, with the progress of speed-up and power-up of internal combustion engine in recent years, the load applied to the bearing is increased as well, thereby giving rise to a problem that fatigue and crack are apt to take place particularly in the intermediate bonding layer. Concerning the latter, on the other hand, it has become eagerly required to have an excellent fatigue strength and such compatibility that the bearing can follow misalignment of the housing and change in the shaft form when used as a main bearing metal of the engine and so forth.